title: Effects of chlorinated bisphenols on torula yeast glucose-6-phosphate dehydrogenase.
abstract: Chlorinated bisphenol antibacterial and antifungal agents are potent inhibitors of torula yeast glucose-6-phosphate dehydrogenase (G6PD). Several compounds were tested, including hexachlorophene [HCP; 2,2'-methylenebis(3,4,6-trichlorophenol)]; 2,2'-oxybis(tetrachlorophenol); 2',4-dihydroxy-2,3,3',5,5',6-hexachlorodiphenylmethane; 2,2'-methylenebis(3,4-dichlorophenol) (3,4-TCP); bithionol [2,2'-thiobis(4,6-dichlorophenol)]; 2,2'-methylenebis(3,5-dichlorophenol); 2,2'-dihydroxy-3,3',5,6,6'-pentachlorodiphenylmethane; 2,2'-methylenebis(4-chlorophenol) (DCP); 2,2'-methylenebis(4,6-dichlorophenol); and the related uncoupler 2,4-dinitrophenol. The relative inhibitory activity of the chlorinated bisphenols tended to increase with degree of chlorination of the aromatic rings. the concentrations of the bisphenols that caused 50% inhibition ranged from 2.5 micrometers for 2,2'-oxybis(tetrachlorophenol) to 40 micrometers for 2,2'-methylenebis(4,6-dichlorophenol) under comparable assay conditions. More detailed kinetic analysis showed that, as with HCP, the inhibition of G6PD by 3,4-TCP and DCP followed noncompetitive kinetics. Calculations from the kinetic data gave apparent inhibition constant (Ki) values for 3,4-TCP of 267 micrometers with G6P and 308 micrometers with NADP, and for DCP of 697 micrometers with both G6P and NADP.
mesh_terms: D000890:Anti-Infective Agents / Q000633:toxicity*; D002175:Candida / Q000201:enzymology*; D004003:Dichlorophen / Q000633:toxicity; D005954:Glucosephosphate Dehydrogenase / Q000037:antagonists & inhibitors*; D006582:Hexachlorophene / Q000633:toxicity; D007700:Kinetics; D011078:Polychlorinated Biphenyls / Q000633:toxicity*
chemical_list: D000890:Anti-Infective Agents; D011078:Polychlorinated Biphenyls; D005954:Glucosephosphate Dehydrogenase; D006582:Hexachlorophene; D004003:Dichlorophen